Ultimate IDI Engine/Transmission Combo for DD/Towing

[icanfixall]

Be sure to balance the rotating parts of the motor. I did mine so that the max differance in piston weight is between 1/3 and 1/4 gram. When you sit in my rig as its idleing you hear the motor but you can't feel or"see" it running. It runs that smooth... Like butta.... Diesel Direct in Florida had two pallets full of turbo rods. Three years ago they cost $42.00 each.... No core either... I bought a set but really should have bought two more sets. I do have a "spare set" here but as its known about me... I like spares.....Always linebore the cylinders to the crank no matter what you do to the cylinders like a resleeve or just bore out to the next size. The cam bearing bore wont matter enough to need attension. The drilling out of the 7/16 bolts and nistalling 1/2 inch head bolts wont work too well. The hole is too big already from the 7/16 cut threads and if you do this you wont have a complete 1/2 thread. You will end up with about 1/2 of a useable thread. The new 1/2 inch bolts have been tested by me and they break at 153,000 psi. ARP studs break at 200 or 220,000 psi... Plus they can be reused almost forever... The 7/16 bolts break much less than that. I have not tested them because I don't build 6.9 motors.... Yet... A persome with a programable mill could install 9/16 studs in the 6.9 motors but thats plenty of work. You will need to drill out the head bolt holes so a 9/16 stud could fit thru them. So how much will you drill oversize... Probably a 19/32 or .5938 drill in the heads. Then you need to be lucky drilling out the block because of the water jackets. So you see whats involved it this approach. Drilling and taping out a block is a big job to any size. You have 34 bolt holes. Thats 34 chances of something going wrong. Then you have a junk block.

 

[1994IDI]

Awesome information here guys, thanks to all.

 

[The Warden]

1. ZF5/ZF6 - My E4OD is very wel built now with all the upgrades and a billet low stall converter, but I'm inclined to go straight

I would stick with the ZF5. The ZF6 will really only give you a granny gear, and with a Brownie box, you'll already have that granny gear...and installing a ZF6 is quite the undertaking and IMHO more trouble than it's worth, not to mention the extra expense involved.

2. Brownie Box 3 spd aux transmission. Most bang for the buck over Gear Venders or US Gear. Based on my understanding probably the most dificult to operate of the 3 though. Enlighten me here if I am wrong. If not Brownie Box then I go with US Gear over Gear Venders because of design. I like the gear setup over hydraulics and the ability to use in reverse.

That assessment sounds about right...I thought about putting a Brownie in my truck, but I decided to go with a U.S. Gear because a) I don't have the fabrication skills to mount a Brownie myself and b) I wasn't all that confident on finding one easily and c) I want to be able to use the gear-splitter in 4H if needed (since the U.S. Gear goes between the tranny and the transfer case on a 4x4; which is the main reason why I went with a U.S. Gear over a GV). Having a nice granny gear along with direct and OD will certainly be a plus.

3. DRW 4.10 rear axle w/discs and LSD or Lock-Rite locker. With this setup in my situation I will exclude 4WD. I don't use it enough.

Makes sense to me...honestly, for a towing rig, unless you live in an area where the weather's such that you need 4 wheel drive, it's really just extra weight that's taking away from your payload, and it's more things to fail. That said, I use "2L" on my transfer case pretty regularly, but with the Brownie, you'll have an effective substitute. One thing to think about...if the low range on your Brownie's low enough, you might consider 3.54 gears instead of 4.10's. This way, your lower gears will still be low enough for what you need, and you'll have an option for even lower freeway cruising RPM's if you want (i.e. when you're empty or lightly loaded). But, that's just my opinion on the matter...others will disagree. I will say that, if you don't use the Brownie, you're better off with 4.10's.

4. Hydroboost brakes.

5. Air Ride for leveling load.

6. 19.5 tires/wheels for extra load capacity. Also, taller gear for highway.

Cooling:
1. Aluminum radiator and MS Tech fan clutch. I like the idea of electric fan if one is available to provide adequate cooling for 26,000# GCWR.

2. If the E4OD is used then aftermarket cooler with electric fan.

Agree fully with all of that, although I'd rather strongly advocate ditching the E4DOA

Engine: (Remember, we are sticking with 6.9/7.3 for purists sake. No Cummins, DTs or others.)
1. 7.3 with sleeves if done right would be great. Otherwise the 6.9 gets my vote due to cavitation and cooling issues.

2. Lower compression thru offset wrist pin pistons that Gary mentioned plus shaving the tops. Can you get thicker head gaskets to eliminate shaving the piston?

#1 makes perfect sense to me as to #2...I don't think that thicker head gaskets exist for these engines, and frankly, if they did, I wouldn't trust them, considering how much compression there is in these engines...for that matter, I'm not sure you can get thicker head gaskets for any diesel, although I could be mistaken.

3. Port and polish heads.

4. Head studs.

5. Turbo/intercooler setup. How big can you go with lower compression? 25# boost?

#3 and #4 sound very good...as to #5, I'm not sure what boost's safe with lower compression, but 25 lbs sounds reasonable, although as others have pointed out, you're probably going to need a PSD (or something similar) turbo at that point. Keep in mind that, if you get the compression ratio lowered enough to handle that sort of boost (in the 17:1 range) by lowering the piston height, the engine's going to be a cast-iron bear to start while cold!!

I have yet to see anyone try this, and it may not be possible, but I've always wondered if it'd be possible to get the compression ratio lowered by modifying the precombustion chambers? If it can be done, IMHO this would be the way to go....better than re-doing pistons because you'll still have all the piston thickness you'll need, and this will leave more air in the precup for the glow plug to heat up and may eliminate the cold-start problem you have with a low-compression IDI.

6. Moose pump and injectors.

7. Oil pump and regulator shims.

8. Typ4 reground camshaft.

9. Line bore crank mains. Should we do camshaft and cylinders also?

10. What about engine balancing? Is it worth the effort/cost?

This just starts the list. Add to it at will.

Sounds like a good start to me! BTW in your searches, did you find the description on how to do the oil pressure regulator shims? I can't for the life of me remember how to do it or find the thread, but that's something I'd like to take care of in the near future...it's not dangerous, but my cruising oil pressure's a bit low for my liking...

 

[tuckerd1]

I would stick with the ZF5. The ZF6 will really only give you a granny gear, and with a Brownie box, you'll already have that granny gear...and installing a ZF6 is quite the undertaking and IMHO more trouble than it's worth, not to mention the extra expense involved.

I agree, with the brownie zf6 would be unnecessary. Also, have read about the zf6 swap being very time consuming.

That assessment sounds about right...I thought about putting a Brownie in my truck, but I decided to go with a U.S. Gear because a) I don't have the fabrication skills to mount a Brownie myself and b) I wasn't all that confident on finding one easily and c) I want to be able to use the gear-splitter in 4H if needed (since the U.S. Gear goes between the tranny and the transfer case on a 4x4; which is the main reason why I went with a U.S. Gear over a GV). Having a nice granny gear along with direct and OD will certainly be a plus.

I haven't found a brownie yet, but I think I have a lead on one for about $400.00. Gotta go check it out. I live in a very hilly (we call 1900' mountains) area with a lot of logging going on for lots of years and I think I can locate one though if this one doesn't pan out.

Makes sense to me...honestly, for a towing rig, unless you live in an area where the weather's such that you need 4 wheel drive, it's really just extra weight that's taking away from your payload, and it's more things to fail.

I agree. Also I have an 84 Toyota that I do my recreational 4w'ing in.

Agree fully with all of that, although I'd rather strongly advocate ditching the E4DOA

If I build this tow rig the E4OD is gone.

I don't think that thicker head gaskets exist for these engines, and frankly, if they did, I wouldn't trust them, considering how much compression there is in these engines...for that matter, I'm not sure you can get thicker head gaskets for any diesel, although I could be mistaken.

I'm fishing here trying to see if anyone knows

I'm not sure what boost's safe with lower compression, but 25 lbs sounds reasonable, although as others have pointed out, you're probably going to need a PSD (or something similar) turbo at that point. Keep in mind that, if you get the compression ratio lowered enough to handle that sort of boost (in the 17:1 range) by lowering the piston height, the engine's going to be a cast-iron bear to start while cold!!

I was pretty sure an upgrade to the turbo would be necessary even though I have not mentioned it. Cold start could be a PITA even though I don't live in a sever cold area.

I have yet to see anyone try this, and it may not be possible, but I've always wondered if it'd be possible to get the compression ratio lowered by modifying the precombustion chambers? If it can be done, IMHO this would be the way to go....better than re-doing pistons because you'll still have all the piston thickness you'll need, and this will leave more air in the precup for the glow plug to heat up and may eliminate the cold-start problem you have with a low-compression IDI.

Sounds like an experiment for icanfixall!

Sounds like a good start to me! BTW in your searches, did you find the description on how to do the oil pressure regulator shims? I can't for the life of me remember how to do it or find the thread, but that's something I'd like to take care of in the near future...it's not dangerous, but my cruising oil pressure's a bit low for my liking...

I didn't come up with the oil pump mods. That was Gary again. You know we are lucky to have icanfixall, typ4 and agnem on this board together. I know there are a lot of others that contribute heavily too so don't get upset because I omitted you.

Warden, thanks for your input. Keep us thinking!

 

[tuckerd1]

BTW, I need to start looking for a complete cheap donor truck! Preferably in 93-94 range for some interior parts I want to modify plus the 7.3 and zf5 i will need to build for this tow rig.

 

[bike-maker]

I see no reason why a thicker head gasket couldn't be used. I've worked on some blown alcohol motors that run the copper head gaskets as thick as .110". The gasket would have to be made out of a copper sheet, and o-ring grooves would have to be machined in the block and heads, so it would get expensive pretty quick. But I do believe it to be possible. When we ran the calculations on one of the motors, factoring in blower boost, IIRC it had the equivalent of 28:1 compression. 12.5:1 static with 35 pounds of boost.
Long story short; the easiest way to knock compression out of these motors would be a custom set of pisons; the same basic piston, but with less compression height (just move the wrist pin up higher in the piston).

On a side note; how about a T-19 and a 3 or 4 speed brownie?